AD 96-17-05 ACTIVE

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Saab Model SAAB SF340A and SAAB 340B series airplanes. This action requires the installation of a mechanical flight idle stop on the control quadrant of the flight compartment. This action also requires a revision of the Airplane Flight Manual to ensure the use of certain operating procedures after the mechanical flight idle stop is installed. Additionally, this action provides an optional terminating action for the requirements of this AD. This amendment is prompted by a report indicating that the means of protection against the selection of the "beta" range of propeller operation during flight has been reduced on certain modified control quadrants. Additionally, there have been reports indicating that power levers on the control quadrant have been moved aft of the flight idle position during flight due to improper usage of the mechanical beta stop. The actions specified in this AD areintended to prevent such movement of the power lever(s) during flight, which could result in propeller overspeed, engine damage, and loss of power to one or both engines.

Final rule; request for comments

96-17-05 SAAB AIRCRAFT AB: Amendment 39-9713. Docket 96-NM-181-AD.
Applicability: Model SAAB SF340A and SAAB 340B series airplanes on which Saab Service Bulletin 340-76-034, dated January 4, 1995; Saab Service Bulletin 340340-76-036, dated December 8, 1995; or Saab Service Bulletin 340-76-037, dated December 8, 1995, have been accomplished; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed bythis AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent the movement of both power levers aft of the flight idle stop during flight, accomplish the following:

(a) For airplanes on which an automatic flight idle stop system has been installed, but deactivated in accordance with Saab Service Bulletin 340-76-036, dated December 8, 1995; or on which a control quadrant in the flight compartment has been installed in accordance with Saab Service Bulletin 340-76-037, dated December 8, 1995: Within 7 days after the effective date of this AD, install a mechanical flight idle stop on the control quadrant in the flight compartment in accordance with Saab Service Bulletin 340-76-034, dated January 4, 1995, and accomplish the requirements of paragraph (b) of this AD.

(b) For airplanes subject to paragraph (a) of this AD; and for airplanes on which a mechanical flight idle stop has been installed on the control panel in accordance with Saab Service Bulletin 340-76-034, dated January 4, 1995, previous to the effective date of this AD: Within 7 days after the effective date of this AD, revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to include the following operating limitations. This may be accomplished by inserting a copy of this AD in the AFM.

"Mechanical Beta Stop Operating Limitations

- The stop must be in the beta open position during all ground operations including takeoff run.

- The stop must be lifted and positioned fully forward and down in the beta stop position during climb-out after take-off.

- The stop must remain in the beta stop position throughout the remainder of the flight until after touchdown.

- The stop must be lifted and positioned in the beta open position immediately after touchdown.

- Landing Field Lengths Requiredmust be increased by 5% and 8% for flap settings 35 and 20, respectively."

(c) Installation and activation of the automatic flight idle stop system in accordance with Saab Service Bulletin 340-76-032, Revision 2, dated December 8, 1995, or Revision 3, dated March 25, 1996; or reactivation of the system in accordance with Saab Service Bulletin 340-76- 038, dated December 8, 1995; constitute terminating action for the requirements of this AD. Once the system has been activated, the mechanical flight idle stop and the AFM revision required by this AD may be removed.

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Standardization Branch, ANM-113, FAA Transport Airport Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113.NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(f) The installation of the mechanical flight idle stop shall be done in accordance with Saab Service Bulletin 340-76-034, dated January 4, 1995. The installation and activation of the automatic flight idle stop system shall be done in accordance with Saab Service Bulletin 340-76- 032, Revision 2, dated December 8, 1995; or Saab Service Bulletin 340-76-032, Revision 3, dated March 25, 1996. The reactivation of the system shall be done in accordance with Saab Service Bulletin 340-76-038, dated December 8, 1995. This incorporation by reference was approved by theDirector of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from SAAB Aircraft AB, SAAB Aircraft Product Support, S-581.88, Link ping, Sweden. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on September 3, 1996.

The FAA has received a report from an operator of a Model SAAB 340B series airplane indicating that, during training, the flightcrew noticed a reduction in the protection associated with movement of the power levers aft of the flight idle position during flight. Moving the power lever settings aft of the flight idle position (or "below flight idle") places the airplane in the "beta" range of operation. "Beta" is the range of propeller operation intended for use only during taxi, ground idle, or reverse operations. If "beta" range is selected, either intentionally or inadvertently, during flight, it could result in propeller overspeed, engine damage, and loss of power to one or both engines.

Automatic Flight Idle Stop Modification
The airplane involved in the incident referred to above was equipped with a modified control quadrant. The installation of a new control quadrant is described in Saab Service Bulletins 340-76-032 and 340-76-037, and is part of the modification necessary to install an automatic flight idle stop system that will automatically prevent movement of the power levers aft of flight idle during flight.

The modification also entails the removal of a certain beta stop protection device that was a basic original feature of the Saab Model 340 series airplanes. This original protection device featured serrations in the power lever assembly that helped to prevent the inadvertent movement of the power levers aft of the flight idle position. The modified control quadrant does not provide these serrations, however, and thus eliminates what would serve as a "back-up" feature for beta stop protection. This is not an issue of concern on airplanes where the automatic flight idle stop system has been installed and activated. However, for airplanes on which the modified control quadrant is installed, but the automatic flight idle stop system is not yet activated, beta stop protection is even further reduced.

Mechanical Flight Idle Stop Modification
Some Saab Model 340 series airplanes have been modified with the installation of a mechanical beta stop mechanism on the control quadrant in accordance with Saab Service Bulletin 340-76-034. (Procedures for installing a mechanical stop are also described in Saab Service Bulletins 340-76-036 and 240-76-037.) This mechanical stop is manually operated and, if used, prevents any power lever from being unintentionally moved into beta range during retardation of the power lever during flight. It is considered to be an interim improvement in beta protection until the automatic flight idle stop system is installed and activated.

While this mechanical stop serves as a means of beta protection, the FAA has received several reports indicating that the flight crew did not use the mechanical stop, or used it improperly, and moved the power levers into the beta range during flight.

Explanation of Relevant Service Information
Saab has issued the following service bulletins that pertain to beta protection devices:

1. Saab Service Bulletin 340-76-034, dated January 4, 1995, describes procedures for installation of a mechanical flight idle stop on the control quadrant in the flight compartment. Accomplishment of this installation is intended to prevent the power levers from being moved aft of the flight idle stop during flight. The Luftfartsverket (LFV), the airworthiness authority for Sweden, has classified this service bulletin as mandatory and issued Swedish airworthiness directive 1-067, dated January 9, 1995, in order to assure the continued airworthiness of these airplanes in Sweden.

2. Saab Service Bulletin 340-76-032, Revision 2, dated December 8, 1995; and Revision 3, dated March 25, 1996; describe procedures for installation and activation of an automatic flight idle stop system on the control quadrant in the flight compartment. The installation involves:

- removing the mechanical beta stop (if installed),

- removing the old control quadrant,

- installing a new/modified control quadrant with an automatic flight idle stop, and

- accomplishing a functional test of the flight idle stop system. Accomplishment of this installation also will prevent the power levers from being moved aft of the flight idle stop during flight. Installation and activation of an automatic flight idle stop, if accomplished, eliminates the need for installation of a mechanical flight idle stop. The LFV classified this service bulletin as mandatory and issued Swedish airworthiness directive 1-070, dated April 10, 1995, in order to assure the continued airworthiness of these airplanes in Sweden.

3. Saab Service Bulletin 340-76-038, dated December 8, 1995, describes procedures to reactivate the automatic flight idle stop system for those systems that have been installed previously, but deactivated in accordance with Saab Service Bulletin 340-76-036. If accomplished, such reactivation also eliminates the need for installation of a mechanical flight idle stop.

The LFV has approved the technical content of this service bulletin.

U.S. Type Certification of the Airplanes
Saab Model SAAB SF340A and SAAB 340B series airplanes are manufactured in Sweden and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement.

Explanation of Requirements of Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to prevent movement of the power lever(s) aft of the flight idle position during flight. That situation could result in the overspeed of the propeller and power turbine of the engines and consequent loss of power to one or both engines, as well as severe engine damage.

This AD requires theinstallation of the mechanical flight idle stop on the control quadrant in the flight compartment in accordance with Saab Service Bulletin 340-76-034, described previously.

To prevent inappropriate usage of this mechanical stop, this AD also requires that the FAA-approved Airplane Flight Manual (AFM) be revised to ensure that the flight crews are advised of the specific limitations necessary to address flight operations when the mechanical flight idle stop is installed.

Additionally, this AD provides for optional terminating action for the requirements of this AD, as installation of the modified control quadrant and activation of the automatic flight idle stop.

Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Interim Action
This AD is considered to be interim action. On March 15, 1996, the FAA issued a notice of proposed rulemaking (NPRM), Docket 95-NM-243-AD (61 FR 11591, March 21, 1996), to require installation and activation of the automatic flight idle stop on certain Saab Model SAAB SF340A and SAAB 340B series airplanes. However, the FAA has determined that the mechanical flight idle stop, as required by this AD, must be provided for certain airplanes in the interim until the automatic flight idle stops are installed and activated.

Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stampedpostcard on which the following statement is made: "Comments to Docket Number 96-NM-181-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-181-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
The service information referenced in this AD may be obtained from SAAB Aircraft AF, SAAB Aircraft Product Support, S-581.88, Linkoping, Sweden. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Ruth E. Harder, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-1721; fax (206) 227-1149.